The subject matter disclosed herein relates generally to magnetic resonance imaging (MRI) systems, and more particularly to a radio frequency (RF) coil array used with a MRI imaging system.
MRI imaging systems use RF coils to acquire image information of a region of interest of a scanned object. The resultant image that is generated shows the structure and function of the region of interest. At least one conventional MRI imaging system includes a multiple-channel array coil having a plurality of coil elements. The signals detected by the multiple-channel array coil are processed by a computer to generate MR images of the object being imaged. During operation, the plurality of coil elements are inductively or capacitively decoupled from the other coil elements. In many cases, inductive decoupling through overlapping of the RF coil elements is preferred. More specifically, in an overlapping configuration, a portion of an RF coil overlaps a portion of an adjacent RF coil. However, in some cases coil underlapping is preferred. In an underlapping configuration, each RF coil is separated from an adjacent RF coil.
Conventionally, good isolation in an overlapped configuration has been achieved using critical coupling wherein the RF coils are overlapped a predetermined distance. Good isolation in an underlapped configuration is typically achieved using transformers disposed between adjacent RF coils. In each of the overlapped and underlapped configurations, the spacing between the RF coils is fixed or pre-determined. Thus, the overall coverage of a conventional RF coil is also fixed. However, RF arrays are typically sized to be utilized with a patient having an average size. Thus, if the patient is larger or smaller than the average patient, the RF coil array may be too large or too small to properly fit the patient. As a result, in operation the RF coil may not provide sufficient information of the patient being imaged. To accommodate larger and smaller patients, some medical facilities may choose to purchase RF array coils having different sizes to accommodate patients having different sizes. However, the costs of such RF coils arrays may limit the quantity of medical providers capable of expending the additional financial resources required to purchase RF coil arrays having different sizes.